Cisco Meraki MX/Meraki Z AnyConnect VPN Server resource consumption

Summaryinfo

A vulnerability marked as problematic has been reported in Cisco Meraki MX and Meraki Z. This impacts an unknown function of the component AnyConnect VPN Server. The manipulation leads to resource consumption. This vulnerability is documented as CVE-2024-20502. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Cisco Meraki MX and Meraki Z (the affected version is unknown). This issue affects an unknown code of the component AnyConnect VPN Server. The manipulation with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. The summary by CVE is:

A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to insufficient resource management while establishing SSL VPN sessions. An attacker could exploit this vulnerability by sending a series of crafted HTTPS requests to the VPN server of an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to stop accepting new connections, preventing new SSL VPN connections from being established. Existing SSL VPN sessions are not impacted. Note: When the attack traffic stops, the Cisco AnyConnect VPN server recovers gracefully without requiring manual intervention.

The advisory is shared at sec.cloudapps.cisco.com. The identification of this vulnerability is CVE-2024-20502 since 11/08/2023. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 241198 (Cisco Meraki 16.2 / 17 / 18.1 < 18.1.07.12 / 18.2 < 18.2.11.2 Multiple Vulnerabilities (cisco-sa-meraki-mx-vpn-dos-QTRHzG2)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (241198) and EUVD (EUVD-2024-18217). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• Cisco

Name

• Meraki MX
• Meraki Z

License

• commercial

Website

• Vendor: https://www.cisco.com/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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